The present invention relates in general to constant velocity universal ball joints, and in particular, to a new and useful universal ball joint which has an outer member, an inner member, a ball cage mounted for rotation between said inner and outer members, and a plurality of torque-transmitting balls captured in said ball cage and mounted for rolling between said inner and outer members.
In constant velocity universal ball joints, it is usual to form the ball tracks or races in the inner and outer ball members, to have a cross-section which is symmetrical across their entire length, when the joint is an undeflected position with respect to the center of the balls. This is done to provide favorable deflection angles and so that the least possible amount of machining is necessary.
If the requirements concerning the deflection angle of the joint are reduced, there is a corresponding reduction in the axial length of the joint members or the lengths of the ball trace regions to be machined.
The machining of the ball tracks or races occurs, as a rule, mechanically in the known joints, particularly by grinding, or by reshaping without cutting. While this avoids excessive expense, only ball tracks that are free of undercuts are possible in the outer joint member, and ball tracks which have equidirectionally reduced center distances are possible in the inner joint member.
A disadvantage in the fabrication of such joints with ball tracks that are free of undercuts and which are produced by reshaping, lies in that a sorting of the joint members must be accomplished prior to assembly. This is because of relatively poor observance of selected dimensional requirements for the joint members. Even after this sorting operation, however, tolerance fluctuations still occur within a specific range. The grinding, or also, only a regrinding of at least one of the joint members which is free of the undercuts or of joint members with equidirectionally reduced axial distance, is, however, frought with considerable difficulty since the required track courses cannot be produced at justifiable expense. As a rule these tracks are composed of circular arcs and straight lines.